Percutaneous interventional technology is a therapeutic method with an increasingly wider application field. A variety of implants, such as a heart defect occluder, a vascular plug, a vascular filter and the like, may be placed into the heart and the artery and vein vessels of the human body by using catheter interventional therapy.
When these implants are implanted into the heart and the artery and vein vessels of the human body through the catheter interventional method, due to the complex anatomical structures of the heart and the artery and vein vessels of the human body, a catheter, a guide wire and a pusher must be used to ensure that the implant reaches a predetermined position. The catheter first reaches the predetermined position under the guidance of the guide wire. A flexible and fine catheter is required during such an operation, while the catheter and the guide wire are designed to provide good radiopaque characteristics under an X ray, After the catheter reaches the predetermined position, the guide wire is removed, and the implant is then accommodated into the catheter, and guided to the distal end of the catheter by the pusher through a channel established by the catheter. When the implant reaches the distal end of the catheter, the implant is released from the catheter by the pusher, and finally will be disconnected from the pusher, so that the implant is released.
In prior implanted medical instruments (hereinafter general terms of implants and pushers), the implants and the pushers are usually in threaded connection or connected by using a connecting wire. For example, a Chinese patent application, of which the application number is 201010265431.2, discloses a device for connecting an implant and a pusher by using a connecting wire. As shown in FIG. 1, the device includes an implant 1a with a closure head 2a, and a pusher 5a; at least one lock ring 9a is arranged on the implant 1a, and a lock 3a having an inner cavity 8a is arranged on the top end of the pusher 5a. The inner cavity 8a of the lock 3a is communicated with a tube cavity 6a of the pusher 5a; the lock 3a is provided with at least one lock hole 7a, and the tube cavity of the pusher 5a is provided with a control wire 4a inside. The control wire 4a, the lock ring 9a and the lock hole 7a are matched with each other to form a plug structure so as to connect the implant with the pusher, and deliver the implant to a predetermined position, wherein the closure head plays the role of fixing the lock ring which plays the role of connecting, and the control wire 4a is withdrawn to achieve release.
The implanted medical instrument mentioned above has the following disadvantages and limitations. 1. The lock ring is formed at the implant; after the implant is implanted into the human body, the lock ring is also implanted into the human body, resulting in the increase in the amount of metal remaining in the human body. This increase of the amount of metal means the increase of the amount of metal elements released in the human body, resulting in unpredictable biological risk, 2. After the implant is implanted into the human body, it is possible that the lock ring and the surface of the implant are not fitted closely; so that the endothelial tissue subsequently may not completely cover the lock ring, thereby resulting in a thrombus source at the implant.